Does El Niño Mean A Warmer Winter For Connecticut?

Forecasters believe a strong El Niño could be brewing in the eastern tropical Pacific Ocean, which could herald some profound weather changes in the continental U.S.

El Niño refers to the warming of ocean waters in the Pacific. Its counterpart, La Niña, refers to cooling of the same waters. There isn’t an El Niño yet, but forecasters from the National Weather Service say “the chances of El Niño increase during the reminder of the year, exceeding 50 percent by summer.” Underwater temperatures have been on the rise, which “reflect[s] a clear evolution toward an El Niño state,” according to the NWS.

How that affects global weather patterns is, to say the least, complicated. But some common weather effects have been observed during El Niño years, including warmer and drier winters in the Pacific Northwest, northern Midwest and northern Mideast United States. Wetter winters have been reported in the southwest United States, including central and southern California, which is withering from drought, according to the NWS’s Climate Prediction Center.

What does this mean for Connecticut?

The long-term forecast suggests warmer-than-normal temperatures for New England for the next year. But what has happened here during previous El Niño years?

There have been six “strong” El Niño years since 1950, according to the NWS. The average winter temperatures recorded at Bradley International Airport were above the 110-year average during five of those six years.

During the winter of 1997-98, for example, which featured the strongest El Niño recorded in the last 64 years, the average temperature at Bradley from December through February was 33.4 degrees — nearly 5 degrees above average. It was the fourth-warmest winter of the last century and saw only 20 inches of snow, which is less than half of average.

On the other hand, some of Connecticut’s coldest winters featured weak El Niños, and the winter of 1998-99, when the average December-February temperature was more than 3 degrees above average, featured a moderate La Niña.

This past winter, for all its brutality, had neutral conditions in the Pacific.

For more about the puzzling effects of the ENSO oscillation, visit the NWS here.